title: A bridging study between liquid chromatography and microbial inhibition assay methods for determining amoxicillin residues in catfish muscle.
abstract: A bridging study was conducted to establish the correlation between a liquid chromatographic (LC) method and a microbial inhibition (MI) method for analysis of amoxicillin residues in catfish muscle. The LC procedure involved precolumn derivatization with formaldehyde followed by LC separation with fluorescence detection. The MI procedure used Bacillus stearothermophilus as the test organism and was validated in this study before the bridging investigation. The 2 methods were compared for determination of both fortified and incurred samples. No significant differences were found between the methods when all data were included in statistical computations. The linear correlation of LC means versus MI means had a slope of 0.972 and a negligible intercept (1.0 ng/g), with a correlation coefficient of 0.9962. LC was more specific and showed better sensitivity than MI for amoxicillin residues at < or = 10 ng/g. For practical purposes, values obtained by the 2 methods can be considered equivalent.
authors.affiliation: U.S. Food and Drug Administration, National Center for Toxicological Research, Division of Chemistry, Jefferson, AR 72079-9502, USA.
authors.forename: C Y
authors.initials: CY
authors.lastname: Ang
authors.forename: W
authors.initials: W
authors.lastname: Luo
authors.forename: C R
authors.initials: CR
authors.lastname: Kiessling
authors.forename: K
authors.initials: K
authors.lastname: McKim
authors.forename: R
authors.initials: R
authors.lastname: Lochmann
authors.forename: C C
authors.initials: CC
authors.lastname: Walker
authors.forename: H C
authors.initials: HC
authors.lastname: Thompson
mesh_terms: D000658:Amoxicillin / Q000008:administration & dosage / Q000032:analysis* / Q000494:pharmacology; D000818:Animals; D017756:Aquaculture; D002853:Chromatography, Liquid / Q000662:veterinary; D003470:Culture Media; D004350:Drug Residues / Q000032:analysis*; D001411:Geobacillus stearothermophilus / Q000187:drug effects; D007059:Ictaluridae / Q000378:metabolism*; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D014481:United States; D014486:United States Food and Drug Administration
chemical_list: D003470:Culture Media; D000658:Amoxicillin